In Tim Ferriss' latest book, "Tools of Titans," which explores the daily routines andhabits of world-class performers, the author asks Dorsey about the most worthwhile investment he's ever made —and it isn't in a tech company, stock or real estate.

"Taking the time to walk to work every day," the self-made billionaire tells Ferriss. "Five miles, one hour and 15 minutes."

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Jack Dorsey, CEO of Twitter.

During the five-mile trek, Dorsey unplugs. He doesn't email or text. He uses the time to listen to music and audio books, or simply to think and draw inspiration from the streets of San Francisco.

"It's a very clearing time," he tells CNN Money. "I want to put as much unexpected potential in front of me because I think something that you don't plan will always make you think differently."